An investigation of the use of organic solvents to remove stains of stains from historical paper is reported. Data quoted in biochemical publications supports this approach with several examples can of the use of organic solvents to obtain fungi dyes as testing material. The experimental results indicate the following: 1) stains originating from various species of fungi were removed with only partial efficiency by organic solvents; 2) stains of <i>Epicoccum</i> sp., <i>Chaestomium</i> sp., and <i>Trichoderma</i> sp. appeared to be the easiest to remove. The stains due to overgrowth by Dematiaceae (<i>Cladosporium</i> sp., <i>Stemphylium</i> sp.) were difficult to remove; 3) the best results were obtained with the use of methanol, ethanol, and acetone for extraction. The application of heated solvents improved the stains solubility only to a moderate degree; 4) fungi stains not easily removed by organic solvents were impossible to remove by bleaching with Chloramine T, in spite of acidification of the solution; 5) sterilization by Rotanox had no effect on the solubility of fungi dyes. Sterilization in the vapors of PCMC made the stains more pronounced, and slightly reduced their solubility; 6) the type of paper sizing influenced the number and intensity of stains on a paper sample but did not affect the solubility of dyes; 7) in conservation practice, swabbing of fungi stains with heated ethanol prior to the proper restoration treatment, e.g., bleaching with chloramine T, can improve efficiency of removal of this type of stain.